I found this image on the official website's uploaded screenshot section:

I'm guessing this is from the Guro Station training center quest, the one Bitna quest I haven't done in the area. Because I haven't seen it myself. But it does appear that we do in fact, get a glimpse of Ruvia ingame!

.....Even though they're still obscuring her. But hey, at least we get to see at least one of the other Wolfdogs interacting with Nata. They really feel less like a team and more like Nata doing things himself the way they're not even showing any of the other Wolfdogs save brief shots of Ruvia. Whereas we got to see all five Black Lambs together in their tutorial intro and their Season 1 ending video. (Wolfdogs' is a conversation with Mr. Trainer and Kim Mask. Not even Nata is in it.)

Zzzzz...why do they hide so much?
Beside,Nata was revealed since day 1,(kinda) revia was hinted multiple times with her shadow/silhouette showing a glimpse of her face only (or is she supposed to be like that LOL?),and the 3rd character? we only know there is a third.
;___________________;'

Because Wolfdog aren't necessarily a team like the Black Lambs, they're more just working in the same division, co-workers. This isn't fact, this is just how I've gathered it. Even the Black Lambs seem to be usually just Seha/Seulbi/Yuri, and J/Tein